FURTHER OBSERVATIONS ON PRUNING.
Every forester is aware, that when feeders are pruned off, they should be cut away as close as possible to, and without tearing the hole. To perform this without danger of injury to the tree, when feeders of considerable size are to be removed, the branch should first be sawn over at about one foot beyond the intended section, and a second section then performed at the proper place. This{118}requires a little more time, but not nearly so much as an inexperienced person would suppose, as the section a foot out is made very quickly, and the pruner generally takes as much time to reach the branch as to cut it off. The neatness and advantage of this method will be acknowledged by those who have seen it practised, to compensate for the longer time it requires.
We find the saw, shears, and knife, the best instruments for pruning; in some cases of difficult approach, the long-handed pruning-iron may be resorted to. When the lopping is performed by a percussion tool, the wood and bark at the section is often shattered by the blow, and thence is less likely to cicatrize soundly; and even when executed in the best manner, the surface of the section is smooth and hard, consequently a good conductor of heat, dries much, and thence shrinks and cracks near the centre of the cut, opening a deep crevice, into which the rain penetrates, and often rots deep into the stem. When the section is made by the saw, a slight fibrous clothing is left upon the place, which in some measure protects the ends of the cut tubes from the frost and drying air, and excludes the heat; in consequence the wood at the section does not lose its vitality so far inward, and is not so liable to shrink{119}and crack in the centre and receive rain. The section can also generally be made much neater and closer by the saw than by any other instrument. The common erroneous belief, that a section by a sharp-edged instrument is less injurious than by the saw, is merely hypothetical, from wide analogy from animals. The pernicious influence on the whole individual, received and transmitted by the nerves from mangled section of animal fibre, is probably entirely awanting in vegetables; the whole process of life and of cicatrization is also totally different.
The forester should also be very wary in cutting off a considerable branch, whose section would incline upwards, as such a section, when it has received a circle of new bark and wood, forms a cup which receives and contains rain water, which quickly corrupts the bottom of the cup, and often rots the centre of the tree down to the ground. It is better to crop such a branch several feet from the main stem, close by some small feeder, unless the branch be dead. In pruning, every considerable section should be as near as possible at right angles with the horizon, or rather inclining inward below. Of naval timber, the beech is by far the most likely to take rot by being pruned, and should never have a large limb cut off, as the divided fibres generally die{120}downward a number of feet below the section, and soon afterward decay, leaving a hole in the bole.
As nothing retards the growth of trees more than full flowering and seeding, if pruning diminish this flowering and seeding, so that the gain from the prevention of this exhaustion more than counterbalances the loss of the pruned-off part, the pruning will of course accelerate the growth of the tree; but the removal of lower branches, although in the first place promotive of growing buds and extension of the top, in a year or two longer only tends to throw the tree more into flowering and seeding. The rich dryness, or want of fluidity of the juices which occasions flower-buds, is also induced by hot, dry atmosphere, and short supply of moisture from the roots during the preceding summer, both of which disposing causes are increased by a long naked stem. When the proportion of the part above ground of a tree to the roots is diminished, growing buds result, at least to a certain extent; yet it would be very difficult to practise a proper system of pruning on this principle, as the consequent lengthened stem is, in the end, promotive of flower-buds, especially in dry seasons, and the loss of feeders might greatly counterbalance the gain from not flowering, did a succession of wet cold seasons follow.{121}
The season when pruning should be performed, is something dependent upon the kinds, whether they bleed when pruned in early spring or do not. Almost any convenient time will suit for pruning the latter, but we rather prefer March, April, May, June, or autumn after the leaf has fallen. The former, sycamore, maple, birch, &c. ought either to be pruned in autumn, or after the buds are beginning to break in spring, as they bleed and suffer considerable exhaustion when pruned in the latter part of winter or early spring. From some facts, we consider that pruning in winter, especially in severe weather, gives a check to the vigour of the tree; others agree with this.